The Study of Life

Which of the following statements about T cells is false? 

1. Helper T cells release cytokines while cytotoxic T cells kill the infected cell.
2. Helper T cells are CD4⁺, while cytotoxic T cells are CD8⁺.
3. MHC II is a receptor found on most body cells, while MHC I is a receptor found on immune cells only.
4. The T cell receptor is found on both CD4⁺ and CD8⁺ T cells.

In the example below, the scientific method is used to solve an everyday problem. Match the scientific method steps (numbered items) with the process of solving the everyday problem (lettered items). Based on the results of the experiment, is the hypothesis correct? If it is incorrect, propose some alternative hypotheses. 

1. Observation                a. There is something wrong with the electrical outlet. 

2. Question                    b. If something is wrong with the outlet, my                                                               coffeemaker also won’t work when plugged into it. 

3. Hypothesis (answer) c. My toaster doesn’t toast my bread. 

4. Prediction                  d. I plug my coffee maker into the outlet. 

5. Experiment                e. My coffeemaker works. 

6. Result                         f. Why doesn’t my toaster work? 

 Which of the following statements about mechanoreceptors is false? a. Pacini corpuscles are found in both glabrous and hairy skin. b. Merkel’s disks are abundant on the fingertips and lips. c. Ruffini endings are encapsulated mechanoreceptors. d. Meissner’s corpuscles extend into the lower dermis.

Which of the following statements about the

kidney is false?

a. The renal pelvis drains into the ureter.

b. The renal pyramids are in the medulla.

c. The cortex covers the capsule.

d. Nephrons are in the renal cortex.

Which of the following statements is false? 

a. Choanocytes have flagella that propel water through the body. 

b. Pinacocytes can transform into any cell type. 

c. Lophocytes secrete collagen. 

d. Porocytes control the flow of water through pores in the sponge body 

Figure 10.13 Rb and other proteins that negatively regulate the cell cycle are sometimes called tumor suppressors. Why do you think the name tumor suppressor might be appropriate for these proteins?

Which of the following statements about the male reproductive system is false? a. The vas deferens carries sperm from the testes to the penis. b. Sperm mature in seminiferous tubules in the testes. c. Both the prostate and the bulbourethral glands produce components of the semen. d. The prostate gland is located in the testes. 

Do you think Dolly was a Finn-Dorset or a Scottish Blackface sheep? 

Based on what you know about MHC receptors, why do you think an organ transplanted from an incompatible donor to a recipient will be rejected? 

Which of the following statements about the nephron is false?

a. The collecting duct empties into the distal convoluted tubule.

b. The Bowman’s capsule surrounds the glomerulus.

c. The loop of Henle is between the proximal and distal

convoluted tubules.

d. The loop of Henle empties into the distal convoluted

tubule.

Pancreatic tumours may cause excess secretion of glucagon. Type I diabetes results from the failure of the pancreas to produce insulin. Which of the following statement about these two conditions is true? 

a. A pancreatic tumour and type I diabetes will have the opposite effects on blood sugar levels. 

b. A pancreatic tumour and type I diabetes will both cause hyperglycemia. 

c. A pancreatic tumour and type I diabetes will both cause hypoglycemia. 

d. Both pancreatic tumours and type I diabetes result in the inability of cells to take up glucose. 

Which of the following statements about the anatomy of a mollusk is false? 

a. Mollusks have a radula for grinding food. 

b. A digestive gland is connected to the stomach. 

c. The tissue beneath the shell is called the mantle. 

d. The digestive system includes a gizzard, a stomach, a digestive gland, and the intestine. 

Figure 43.15  Which of the following statements about hormone regulation of the female reproductive cycle is false? a. LH and FSH are produced in the pituitary, and estradiol and progesterone are produced in the ovaries. b. Estradiol and progesterone secreted from the corpus luteum cause the endometrium to thicken. c. Both progesterone and estradiol are produced by the follicles. d. Secretion of GnRH by the hypothalamus is inhibited by low levels of estradiol but stimulated by high levels of estradiol 

Which of the following statements about diploblasts and triploblasts is false? 

a. Animals that display radial symmetry are diploblasts. 

b. Animals that display bilateral symmetry are triploblasts. 

c. The endoderm gives rise to the lining of the digestive tract and the respiratory tract. 

d. The mesoderm gives rise to the central nervous system. 

The Rh antigen is found on Rh-positive red blood cells. An Rh-negative female can usually carry an Rh-positive fetus to term without difficulty. However, if she has a second Rh-positive fetus, her body may launch an immune attack that causes hemolytic disease of the newborn. Why do you think hemolytic disease is only a problem during the second or subsequent pregnancies? 

In the reproductive cloning of an animal, the genome of the cloned individual comes from ________. 

a. a sperm cell 

b. an egg cell 

c. any gamete cell 

d. a body cell 

Which of the following statements about the circulatory system is false? 

a. Blood in the pulmonary vein is deoxygenated. 

b. Blood in the inferior vena cava is deoxygenated. 

c. Blood in the pulmonary artery is deoxygenated. 

d. Blood in the aorta is oxygenated.

Which of the following statements is false? 

a. The parasympathetic pathway is responsible for relaxing the body, while the sympathetic pathway is responsible for preparing for an emergency. 

b. Most preganglionic neurons in the sympathetic pathway originate in the spinal cord. 

c. The slowing of the heartbeat is a parasympathetic response. 

d. Parasympathetic neurons are responsible for releasing norepinephrine on the target organ, while sympathetic neurons are responsible for releasing acetylcholine. 

Loop diuretics are drugs sometimes used to treat hypertension. These drugs inhibit the reabsorption of Na+ and Cl- ions by the ascending limb of the loop of Henle. A side effect is that they increase urination. Why do you think this is the case? 

Figure 6.14One ATP molecule's hydrolysis releases 7.3 kcal/mol of energy (∆G = −7.3 kcal/mol of energy). If it takes 2.1 kcal/mol of energy to move one Na+across the membrane (∆G = +2.1 kcal/mol of energy), how many sodium ions could one ATP molecule's hydrolysis move?

Which of the following statements about insects is false?

a. Insects have both dorsal and ventral blood vessels. 

b. Insects have spiracles, openings that allow air to enter the tracheal system. 

c. The trachea is part of the digestive system. 

d. Most insects have a well-developed digestive system with a mouth, crop, and intestine 

Which of the following is a barrier against pathogens provided by the skin?

1. high pH
2. mucus
3. tears
4. desiccation

Why are open circulatory systems advantageous to some animals? 

a. They use less metabolic energy. 

b. They help the animal move faster. 

c. They do not need a heart. 

d. They help large insects develop.

The forearm consists of the: 

1. radius and ulna 
2. radius and humerus 
3. ulna and humerus  
4. humerus and carpus 

When a dehydrated human patient needs to be given fluids intravenously, he or she is given:

a. water, which is hypotonic with respect to body fluids

b. saline at a concentration that is isotonic with respect

to body fluids

c. glucose because it is a non-electrolyte

d. blood

Which form of reproduction is thought to be best in a stable environment? a. asexual b. sexual c. budding d. parthenogenesis 

Although interferons have several effects, they are particularly useful against infections with which type of pathogen?

a. bacteria

b. viruses

c. fungi

d. helminths

Some animals use diffusion instead of a circulatory system. Examples include: 

a. birds and jellyfish 

b. flatworms and arthropods 

c. mollusks and jellyfish 

d. none of the above

The sodium ion is at the highest concentration in:

a. intracellular fluid

b. extracellular fluid

c. blood plasma

d. none of the above

How many nucleotides are in 12 mRNA codons? 

a. 12 

b. 24 

c. 36 

d. 48 

Insulin produced by molecular cloning: 

a. is of pig origin 

b. is a recombinant protein 

c. is made by the human pancreas 

d. is recombinant DNA 

Which organelle do phagocytes use to digest engulfed particles?

a. lysosome

b. nucleus

c. endoplasmic reticulum

d. mitochondria

Why are steroids able to diffuse across the plasma
membrane?
a. Their transport protein moves them through the
membrane.
b. They are amphipathic, allowing them to interact
with the entire phospholipid.
c. Cells express channels that let hormones flow down
their concentration gradient into the cells.
d. They are non-polar molecules.

Cells in a hypertonic solution tend to:

a. shrink due to water loss

b. swell due to water gain

c. stay the same size due to water moving into and out

of the cell at the same rate

d. none of the above

Which innate immune system component uses MHC I molecules directly in its defense strategy?

a. macrophages

b. neutrophils

c. NK cells

d. interferon

The macula densa is/are:

a. present in the renal medulla.

b. dense tissue present in the outer layer of the kidney.

c. cells present in the DCT and collecting tubules.

d. present in blood capillaries.

If glucose is absent, but so is lactose, the lac operon will be ________. 

a. activated 

b. repressed 

c. activated, but only partially 

d. mutated 

White blood cells: 

a. can be classified as granulocytes or agranulocytes 

b. defends the body against bacteria and viruses 

c. are also called leucocytes 

d. all of the above

Which of the following is both a phagocyte and an antigen-presenting cell?

a. NK cell

b. eosinophil

c. neutrophil

d. macrophage

The osmolarity of body fluids is maintained at ________.

a. 100 mOsm

b. 300 mOsm

c. 1000 mOsm

d. it is not constantly maintained

For a neuron to fire an action potential, its membrane must reach ________. 

a. hyperpolarization 

b. the threshold of excitation 

c. the refractory period 

d. inhibitory postsynaptic potential 

External fertilization occurs in which type of environment? 

a. aquatic b. forested c. savanna d. steppe 

Which immune cells bind MHC molecules on APCs via CD8 coreceptors on their cell surfaces?

a. TH cells

b. CTLs

c. mast cells

d. basophils

In humans, the plasma comprises what percentage of the blood? 

a. 45 percent 

b. 55 percent 

c. 25 percent 

d. 90 percent 

The gland located at the top of the kidney is the ________

gland.

a. adrenal

b. pituitary

c. thyroid

d. thymus

If you were to burn your epidermis, what receptor type would you most likely burn? a. free nerve endings b. Ruffini endings c. Pacinian corpuscle d. hair receptors

While collecting specimens, a marine biologist finds a sessile Cnidarian. The medusas that bud from it swim by contracting a ring of muscle in their bells. To which class does this specimen belong? 

a. Class Hydrozoa 

b. Class Cubozoa 

c. Class Scyphozoa 

d. Class Anthozoa 

The ara operon is an inducible operon that controls the production of the sugar arabinose. When arabinose is present in a bacterium it binds to the protein AraC, and the complex binds to the initiator site to promote transcription. In this scenario, AraC is a(n) ________. a. activator b. inducer c. repressor d. operator

What “self” pattern is identified by NK cells?

a. altered self

b. missing self

c. normal self

d. non-self

10. Which of the following is a water-soluble vitamin? 

a. vitamin A 

b. vitamin E 

c. vitamin K 

d. vitamin C